Door-knob alarm.



PATENTED JUNE-30, 1903.

C. H. AHLUM. DOOR KNOB ALARM.

APPLICATION FILED AUG. 13, 1902.

N0 MODEL.

UNITED STATES Fatented June 30, 1903.

CHARLES H. AHLUM, OF LANSDALE, PENNSYLVANIA.

DOOR-KNOB ALARM.

sPEoIFIcA'r'Ioiv forming part of Letters Patent No. 732,491, dated June 30, 1903.

Application filed August 13, 1902, Serial No. 119,487. lNo modeh) I To aZZ whom it may concern.-

Be it known that I, CHARLES H. AHLUM, a citizen of the United States, residing at Lansdale, in the county of Montgomery, State of Pennsylvania, have invented a new and useful Improvement in Door-Knob Alarms, of which the following is a specification.

My invention consists of a door-knob alarm in which a bell may be rung by the action of the mechanism connected with the spindle on the knob, due to the rotation of the knob and the position of a setting-piece, as will be hereinafter described.

It also consists of a train of gearing including a spring which is wound by the rotation of the bell employed, said winding also causing the locking of the bell-hammer, whereby when said setting-piece is in position the retation of the knob causes the release of said hammer, so as to ring the bell, and thus sound an alarm, the construction of the parts being also such that when said setting-piece is prop-- erly operated the alarm is thrown off and the knob may be turned to operate the door-knob, as usual, without affecting the alarm mechanism.

Figure 1 represents a perspective view of a door-knob alarm embodying my invention. Fig. 2 represents a central longitudinal section thereof.- Figs. 3 and 4. represent views of the interior of difierent portions of the alarm mechanism. 'Fig. 5 represents a section of a portion on line a; 00, Fig. 1. Fig. 6 represents a perspective View of adetached portion.

Similar letters of reference indicate corresponding parts in the figures.

Referring to the drawings, A represents a door-kn ob on the exterior portion of the spindle B, and O designates a door-knob on the interior portion thereof, the knob O consisting in part of the shell or casing D and the bell E. Within the inner portion of the spindle B is the sliding bar F, which is provided with the stud G, which projects at an angle therefrom and protrudes through the slot H in said spindle and when in normal position is adapted to play between the shoulders J on the collar K that stationarily surround the spindle B, so that the knob may be turned in either direction, as usual in such cases, limited by said shoulders. Connected with the bar F is the spring L,which in the present instance is secured to the casing D," the tendency of said spring being to return the bar F to its normal position and hold it therein.

On the escutcheon M is mounted the sliding plate N, on which are the oppositely-disposed cams P, on which the stud G is adapted to move, it being seen in Fig. 1 that when the alarm is not in service the plate N is so operated that the cams P are removed from the path of the stud G; but when the alarm is to be set the plate is shifted so that the cams P move between the shoulders J of the collar K, and the stud G enters the space between the lowest points of said cam. (See Fig. 5.) Now should anyone rotate either knob the stud G will ride on one of the cams P and so be moved in the direction of the length of the spindle, whereby a sliding motion is imparted to the bar F in the direction of the bell E.

Q designates a train of gearing including the escapement R, the bell-hammer S thereon, and the spring '1, the latter being adapted to be Wound by the rotation of the bell E, within which said gearing, escapement, and bell-hammer.are contained, the spring being within the casing D. On the arbor U of the gearing and spring is the ratchet V, with which engages the spring-pressed dog W on the slide X on the plate X of the framework of the gearing, &c., said slide having slots therein for the passage of connecting-sc ews and being engaged by the spring Y for returning it to its normal position, said slide Mounted on the plate X is the springother limb Z adapted to engage the end of or a shoulder Z on the slide X.

It will now be seen that when the bell is ro- 9 tated to wind the spring T the ratchet V is also rotated, whereby one of-its teeth in their motion presses against the dog W and moves the same, causing the nose X to move against the bell-hammer S and controlling the latter oo of the spring engages said shoulder and locks the slide, preventing motion thereof. The winding of the spring T by the bell may continue while the ratchet V rides freely against or under the end of the dog \V without affecting the latter. Now when the plate N is set for operation of the alarm the cams P are in the path of the stud G, as has been stated. Should the knob be turned, especially from the outside, the action of said stud on either of said cams imparts sliding motion to the bar F and causes the end of the bar to press against the limb Z of the lever Z, thus raising the limb Z of the same. This relieves the slide X when the latter under the pressure of its spring Y is moved, so that the nose X of said slide releases the bell-hammer, whereby the latter is free to vibrate and its head immediately strikes and rings the bell, causing an alarm. \Vhen the bell is again rotated, the slide X is again set by the ratchet and dog, so as to lock the bell-hammer and to be engaged by the lever Z when the ringing of the bell ceases. The plate N may also be moved, and thus the alarm may be thrown 05, while either knob may be turned in either direction to operate the bolt, as usual.

On the spindle B is a pin 13, which projects at an angle therefrom and is adapted to enter the recess 13 in the door and abut against the back of the plate or escutcheon M. By this provision the spindle may be prevented from being pushedin from the outside to force the stud G clear of the cams P and permit the rotation vof the knob without operating the alarm.

Various changes may be made in the details of construction without departing from the general spirit of my invention, and I do not, therefore, desire to be limited in each case to the same.

Having thus described myinvention, what I claim as new, and desire to secure by Letters knob to operate the door-bolt Without affecting said controlling device of the train.

2. In a door-knob alarm, a knob-spindle, a sliding bar thereon, a projecting piece on said bar, a movable plate adjacent to said piece, a cam on said plate on which said piece may ride on the rotation of said bar, an alarm mechanism and a lever adapted to be engaged by said sliding and rotatable bar and to engage a member of said alarm mechanism.

In a door-knob alarm, a hell or alarm, a train ofgeariug, a spring adapted to be wound by said bell, a ratchet on the arbor of said gearing, a slide on the support of said gearing, a member on said slide adapted to be en gaged by a tooth of said ratchet to move said slide in one direction, and means on said slide adapted to engage with the hammer of said bell and control the same.

4. In a door-knob alarm, a bell or alarm, a train of gearing, a spring adapted to be wound by said bell, a ratchet on the arbor of said gearing, a slide on the support of said gearing, a member on said slide adapted to be engaged by a tooth of said ratchet to move said slide in one direction, means on said slide adapted to engage with the hammer of said bell and control the same, and a device on said support adapted to prevent return motion of said slide.

5. In a door-knob alarm, a bell or alarm, a train of gearing, a spring adapted to be wound by said bell, a ratchet 011 the arbor of said gearing, a slide on the support of said gearing, a member on said slide adapted to be engaged by a tooth of said ratchet to move said slide in one direction, means on said slide adapted to engage with the hammer of said bell and control the same, a device on said support adapted to engage with said slide and prevent returning motion of the latter, and a movable member on the knob adapted to operate said device and thereby release said slide and with it the controlling means on the bell-hammer.

6. In a door-knob alarm, a rotatable bell or alarm, a train of gearing, a spring adapted to be wound by said bell, a spring-pressed slide on the support of said train of gearing, means for advancing said slide, a nose on said slide adapted to engage the hammer of said bell and hold the same immovable, and a lever on said support adapted to engage said slide and prevent return motion thereof.

7. In a door-knob alarm, a rotatable hell or alarm, a train of gearing, a spring adapted to be wound by said bell, a spring-pressed slide on the support of said train of gearing, means for advancing said slide, a nose on said slide adapted to engage the hammer of said bell and hold the same immovable, and a movable memberon the knob-spindle adapted to be operated by the rotation of the knob and engage said lever thus releasing said slide and consequently the bell-hammer.

8. In a door-knob alarm, a spindle, a sliding bar thereon, a projection on said bar, a cam on the knob on which said projection is adapted to ride, and an alarm mechanism, a releasing member of which is adapted to be engaged by said bar, in combination with a projecting piece rotatably secured to said spindle and a plate adapted to be connected with a door, said piece being adapted to occnpy a recess in said door and to abut freely against the interior face of said plate.

CHARLES H. AIILUM. Witnesses:

ELLIOTT, G. DEITCH, HARRY G. SCOTT.

ICQ 

